All the details about what caused the blackout haven't been released yet, but founding developer Matt Mullenweg wrote the following on the company's blog:
...it appears an unscheduled change to a core router by one of our datacenter providers messed up our network in a way we haven’t experienced before, and broke the site. It also broke all the mechanisms for failover between our locations in San Antonio and Chicago. All of your data was safe and secure, we just couldn’t serve it.
But I'm a Very Important Person!
The crash couldn't've come at a more ironic time, seeing as how WordPress.com's revamped VIP program was just announced this week. Designed for extremely high traffic blogs, the program boasts "rock-solid up time" among other perks.
Unfortunately even the elite couldn't avoid WordPress.com's hiccup, leading to a whopping 10.2 million blacked-out blogs and what is estimated to be 5.5 million missed page views.
Meanwhile, the team behind the platform is still trying to figure out exactly what happened, and how they can recover more gracefully in the event that it happens again.
"I know this sucked for you guys as much as it did for us — the entire team was on pins and needles trying to get your blogs back as soon as possible," wrote Mullenweg. "I hope it will be much longer than four years before we face a problem like this again."